Tension turnbuckle

ABSTRACT

A tension turnbuckle comprises first and second bolts having connectors integral therewith, a preloaded spring arranged about the inner end of said second bolt, a turnbuckle housing threaded onto said first bolt for movement thereon and fixed to the outer end of said preloaded spring, an indicator fixed to the inner end of said second bolt and cooperating with a viewing slot within the turnbuckle housing to permit ascertation of the tension of the turnbuckle, and a housing cap arranged to be screwed onto the turnbuckle housing after the proper tension is achieved to lock out the spring and provide a solid metal load path through the turnbuckle from the first bolt to the second bolt.

United States Patent 1191 Jacobson et al.

[ 1 Aug. 7, 1973 TENSION TURNBUCKLE [75] Inventors: Sol H. Jacobson,Bedford; Donald R.

Gorsuch, Northborougli, both of Mass.

[73] Assignee: Sanders Associates, Inc., Nashua,

[22] Filed: Feb. 25, 1972 [21] Appl. No.: 229,450

716,633 12/1902 Hains et al 287/60 x 1,157,72l 10/1915 Price 287/61 XPrimary Examiner-Andrew V. Kundrat Attorney-Louis Etlinger [57] ABSTRACTA tension turnbuckle comprises first and second bolts having connectorsintegral therewith, a preloaded spring arranged about the inner end ofsaid second bolt, a turnbuckle housing threaded onto said first bolt formovement thereon and fixed to the outer end of said preloaded spring, anindicator fixed to the inner end of i said second bolt and cooperatingwith a viewing slot within the turnbuckle housing to permit ascertationof the tension of the turnbuckle, and a housing cap arranged to bescrewed onto the turnbuckle housing after the proper tension is achievedto lock out the spring and provide a solid metal load path through theturnbuckle from the first bolt to the second bolt.

9 Claims, 3 Drawing Figures TENSION TURNBUCKLE The invention hereindescribed was made in the course of or under a contract or subcontractthereunder with the Department of the Army.

BACKGROUND OF THE INVENTION A turnbuckle is a device for tightening arod, a cable or a stay, and has many applications such as for attachingpay loads to various ground vehicles, aircrafts and ships, as well as inrigging systems for towers or other devices that are restrained bycables. One problem with conventional turnbuckles is that there is noindication provided whereby the user can apply a predetermined load intoa cable or similar tension device. Normally, strain gauges or othermeasuring devices are necessitated which are unduly complex and lack anyself reading feature.

Furthermore, certain turnbuckles are provided with preloaded springsthereon so as to limit the amount of force that has to be applied by theuser. When a preloaded spring is a part of the turnbuckle the springitself becomes a part of the spring system in addition to, for example,the cable on which the turnbuckle is used. In cable systems, as well asother systems whereina turnbuckle is employed, it is desirable normallyto have the highest spring rate possible for the system in order toprevent resonances when the cable is in tension. Unfortunately, thepreloaded spring in the turnbuckle generally will have a spring rateorders of magnitude lower than the cable itself has in tension, andsince the overall spring rate for springs in series is somewhat lessthan the lowest spring rate of any spring in the system, which in thecase of the spring loaded turnbuckle would be the preloaded springitself, the cable system would have a low spring rate.

SUMMARY OF THE INVENTION Accordingly, it is an object of this inventionto provide an improved turnbuckle assembly.

It is another object of this invention to provide a turnbuckle assemblyhaving an indicator integral therewith for indicating the tensionapplied thereto.

It is a further objectof this invention to provide a spring loadedturnbuckle having means for locking out the spring after the propertension has been applied thereto.

Briefly, a turnbuckle is provided having a first bolt on one end thereofon which is screwed a first end of a turnbuckle housing. A second boltat the other end of the turnbuckle has a preloaded spring arranged aboutthe inner circumference thereof with the other end of the turnbucklehousing and the bolt assembly together containing the spring. A housingcap is provided to rotate freely about the second bolt, and is threadedinternally to permit threading the housing cap about the end of thehousing near the spring. An indicator system is also provided forindicating the the amount of tension supplied by the turnbuckle. Afterthe turnbuckle is set to the desired tension, the housing can is screwedonto the housing assembly to lockout the preloaded spring precluding anyresonances to be caused thereby.

BRIEF DESCRIPTION OF THE DRAWINGS.

The above-mentioned and other features and objects of this inventionwill become more apparent by reference to the following description,taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a partial cross-sectional and broken view of a turnbuckle inaccordance with the present invention;

FIG. 2 is an alternate indicating device to be used in conjunction withthe turnbuckle of FIG. 1; and

FIG. 3 is another indicating system for the turnbuckle of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. 1, there istherein illustrated a preferred embodiment of the invention comprising aturnbuckle housing 10 having an end cap 12 affixed thereto allowing forrotation of said housing with a wrench. Housing 10 has a hole 14 thereinfor viewing an indicator, as will be described hereinafter. Housing 10also has internal threads 16 and external threads 18 at the right handend thereof. End cap 12 of housing 10 has internal threads thereinand inuse is screwed about an eye bolt 20. Although an eye bolt is illustratedin this embodiment, any connecting means can be employed. For example,the hook bolt shown at the other end of the device could replace the eyebolt, as could any other connecting means for coupling the turnbuckle tothe system in which tension is to be applied.

The second connector for the turnbuckle assembly is provided by a hookbolt.22. A spring 24- is arranged about bolt 22 and is preloaded betweena pair of thrust bearings 26 and 28. Spring 24 is maintained in a fixedposition about bolt 22 by a nut 30 having an indicator portion 31 and astop nut 34 threaded on bolt 22 and working against a locking nut 32 notconnected to bolt 22. In this embodiment of the invention spring 24 is ahelical compression spring which is preloaded in excess of 1,000 pounds.Nut 32 has external threads which mate with the threads 16 of housing10. A housing cap 36 is arranged about bolt 22 for free rotation, and aplain nut 38 is threaded about bolt 22.

The purpose of the turnbuckle assembly is-to produce a load between twoobjects. Eye bolt 20 is attached to one object and hook bolt 22 isattached to the other object. It is required to bring the two objects toI gether with a known force and then retain this force with theequivalent of a solid bar.

Initially the subassembly comprising the preloaded spring 24 and itsretaining members 26, 30, 28, 32, 34, the housing cap 36, and plain nut38 are assembled. The threads of bolt 22 outside nut 30 and .on bothsides of nut 34 are upset during the assembly. The subassembly isinserted into the housing 10. The housing 10 is then screwed onto thelocking nut 32 with sufficient force such that it will be affixedthereto with no movement occurring therebetween during tightening of theturnbuckle. The two bolts'20, 22 are then attached to the objects to beloaded. In operation the housing cap 36 and plain nut 38 are moved tothe right away from the housing 10 by threading the plain nut 38 up thebolt 22. The turnbuckle housing is then turned in a manner so that ittends to thread onto the bolt 20 until the indicator 31 appears in thehole 14 and lines up with the arrows associated therewith. Preferably,indicator 31 is painted white to aid in the alignment. The desired loadhas now been achieved since the position of the hole in housing It) hasbeen predetermined. A space will now exist between locking nut 32 andstop nut 34 at 35. The

taken out of the system by screwing the housing cap 36 onto the externalthreads of the housing until it bottoms against the stop nut 34. Plainnut 38 is then jammed against the housing cap, thus providing a solidmetal load path from the hook bolt 22 to the eye bolt 20. To unload thetension on the turnbuckle, the above procedure is reversed.

The device of FIG. 1 is used wherein only a single load is to beachieved. If other single loads are to be achieved, the hole 14 can bepositioned elsewhere along the housing. If the turnbuckle is to beemployed for various loading applications, then the hole of FIG.

invention, in accordance with specific apparatus, it is to be clearlyunderstood that the description is made only by way of example, and notas a limitation of the scope of our invention as set forth in theaccompanying claims.

We claim: 1. A tension turnbuckle, comprising: first and secondconnection means; a preloaded spring arranged about said secondconnection means; and coupled to one end thereof; means for couplingsaid first and second connection means through said preloaded spring;and adjustable means for providing a solid coupling between said firstand second connection means and capable of locking outsaid preloadedspring from the load path while simultaneously maintaining it under anyone of various degrees of preload.

2. A tension turnbuckle as defined in claim 1, wherein said first andsecond connection means comprise first and second bolts with saidpreloaded spring arranged about the inner end of said second bolt.

3. A tension turnbuckle as defined in claim 2, further including firstand second nuts threaded onto said second bolt, one nut arranged ateither end of said spring and a locking nut arranged intermediate saidsecond nut and said spring, said locking nut being externally threadedand not connected to said second bolt.

4. A tension turnbuckle as defined in claim 3, further including firstand second thrust bearings, said first and second thrust bearingsarranged intermediate said spring and said first nut and locking nut,respectively.

5. A tension turnbuckle as defined in claim 3, wherein said means forcoupling said first and second bolts through said spring includes ahousing coupled to said first bolt and to said locking nut, said housingbeing externally threaded at one end thereof.

6. A tension turnbuckle as defined in claim 5, wherein said solidcoupling means includes a housing cap threaded onto said housing and anut intermediate the end of said second bolt and said housing cap.

7. A tension turnbuckle as defined in claim 5, further includingindicating means arranged on said first nut, said housing having atleast onehole therein to view the position of said indicating means.

8. A tension turnbuckle as defined in claim 7, wherein said housing hasa number of holes therein corresponding to a plurality of predeterminedtensions.

9. A tension turnbuckle as defined in claim 7, wherein said hole iselongated and has graduation markings associated therewith.

1. A tension turnbuckle, comprising: first and second connection means;a preloaded spring arranged about said second connection means; andcoupled to one end thereof; means for coupling said first and secondconnection means through said preloaded spring; and adjustable means forproviding a solid coupling between said first and second connectionmeans and capable of locking out said preloaded spring from the loadpath while simultaneously maintaining it under any one of variousdegrees of preload.
 2. A tension turnbuckle as defined in claim 1,wherein said first and second connection means comprise first and secondbolts with said preloaded spring arranged about the inner end of saidsecond bolt.
 3. A tension turnbuckle as defined in claim 2, furtherincluding first and second nuts threaded onto said second bolt, one nutarranged at either end of said spring and a locking nut arrangedintermediate said second nut and said spring, said locking nut beingexternally threaded and not connected to said second bolt.
 4. A tensionturnbuckle as defined in claim 3, further including first and secondthrust bearings, said first and second thrust bearings arrangedintermediate said spring and said first nut and locking nut,respectively.
 5. A tension turnbuckle as defined in claim 3, whereinsaid means for coupling said first and second bolts through said springincludes a housing coupled to said first bolt and to said locking nut,said housing being externally threaded at one end thereof.
 6. A tensionturnbuckle as defined in claim 5, wherein said solid coupling meansincludes a housing cap threaded onto said housing and a nut intermediatethe end of said second bolt and said housing cap.
 7. A tensionturnbuckle as defined in claim 5, further including indicating meansarranged on said first nut, said housing having at least one holetherein to view the position of said indicating means.
 8. A tensionturnbuckle as defined in claim 7, wherein said housing has a number ofholes therein corresponding to a plurality of predetermined tensions. 9.A tension turnbuckle as defined in claim 7, wherein said hole iselongated and has graduation markings associated therewith.